Retractable filling valve of the lance type



June 12, 1956 G. E. MATTIMOE ETAL 2,750,091

RETRACTABLE FILLING VALVE OF THE LANCE TYPE 2 Sheets-Sheet 1 Filed April 29, 1955 INVENTORg GEORGE E. MATT/M E Big V5]? TT G-STE H/V ATTORNEX United States Patent RETRACTABLE FILLING VALVE OF THE LANCE TYPE George E. Mattimoe, Burlingame, and Everett G. Stelln, San Francisco, Calif., assignors to T. R. Mantes, doing lusliress as T. R. Mantes Company, San Francisco,

This invention relates to an improved liquid filling valve, that is, a valve used for filling containers with liquid. The invention relates particularly to the type of valve known as a lance valve," which is lowered into a container during the filling operation and is then raised out of the container.

The invention solves many problems met in filling con tainers with liquid where aeration must be avoided, and is especially useful with those containers having an opening that is small relative to the container as a whole, such as large drums filled through a small bunghole at the top. When such containers have been filled by dropping the liquid from a valve positioned above the container, there has been excessive splashing and aeration, even if the valve is very close to the bunghole, and frothing, bubbling or saponification has ensued. To cope with this problem, filling valves of the lance type have been developed, utilizing along pipe that can be inserted through the bunghole to a point near the bottom of the container, and the liquid has then been dispensed through a valve at the very bottom of the pipe. The present invention concerns improvements in this type of filling valve and solves problems which other lance valves had failed to solve.

One disadvantage of prior-art lance valves was their excessive height. When the lance was lifted above the container, most of them stood so high that they could not be used in most existing buildings without raising the ceiling of the room. In the present invention the filling lance telescopes into a stationary housing, so that the overall height of the filling apparatus remains the same, regardless of the position of the lance, and need be only twice the height of the container itself. Therefore, the invention can be used without having tomake any building alterations.

Another problem with lance valves heretofore in use was that the hose through which the liquid was piped into the valve had to be raised and lowered each time the lance itself was raised and lowered. The present invention has solved that problem by providing a stationary housing to which the hose is attached, so that the hose remains stationary during the operation of the valve.

Another problem was that lance valves heretofore in use often leaked from the lower end after the valve was supposed to be closed. This meant that excess liquid dripped into the container after measurement had been completed, or that the container was dirtied by drops falling on the outside walls. The present invention solves this problem by providing a very tight, novel closure arrangement at the lower end of the lance valve, so that there is no dripping.

In the prior art, liquid around the outside walls of a retracted lance also tended to drip back into the container or on its outside walls. Moreover, the liquid which did not drip back inside was liquid which had been weighed as part of the net contents, so the net weight was inaccurate. The present invention solves this problem, by wiping the lance perfectly clean on its upward stroke.

When lance valves are used with inflammable or explosive liquids, the danger of ignition or explosion is always present. This invention achieves safety by pneumatic operation. No electricity is used. By employing non-ferrous metals throughout, all danger of sparking is eliminated.

In addition to achieving the objects of solving the preceding problems, the present invention, as will be later seen, provides several additional novel safety features. It also has other advantages: it is a self-contained unit; all its parts move rectilinearly; no eccentric loads are placed on any parts; and the shape of the valve helps to position the lance in the bunghole, so that the lance is self-locating, once the bunghole is approximately positioned.

The structure which has solved these problems and achieved these objects comprises a pneumatically operated, telescoping, lance valve. Its liquid supply hose is attached adjacent the lower end of its stationary housing, whose upper end is closed and whose lower end is open. A pair of wiping and sealing members are positioned in the housing, one above and one below the liquid inlet. An inner movable cylinder or lance, adapted to telescope within this housing, can be projected out from it to a point near the bottom of the container to be filled. The closure valve at the bottom of the lance is secured to a central rod mounted for axial movement in said lance. At the upper end of this rod is a piston which divides part of the housing interior into two air chambers, air being introduced into either chamber depending on which direction the rod is to be moved. The rod and lance are so linked that movement of the rod effects movement of the lance at the desired time.

Other objects and advantages of the invention will become apparent from the following description of a preferred embodiment thereof, given in accordance with 35 U. S. C. 112.

In the drawings:

Fig. l is a view in perspective of a lance-type filling valve, embodying the principles of the present invention, shown mounted on the frame of an automatic weighing device. A container to be filled by the valve is indicated in broken lines, and the lance is shown in its extended or filling position down inside the container.

Fig. 2 is a view of a portion of Fig. 1, showing the lance in its retracted position.

Fig. 3 is an enlarged view in elevation and in section of the lance valve shown in its fully retracted and closed position, the parts being broken in the center to conserve space.

Fig. 4 is a view generally similar to Fig. 3 with some parts shown in round instead of in section and showing the lance in its extended position, but with the valve still closed.

Fig. 5 is a view similar to Fig. 4, but with the valve open.

Fig. 1 shows a container 10 (in broken lines) resting on a weighing platform 11 of a scale 12, where it is to be filled with a predetermined weight of liquid 13. The container 10 (shown by way of example) is a large drum whose only opening is a bunghole 14 in its top wall 15. The present invention comprises a lance valve, shown generally at 16, to which is attached a hose 17 leading from a large liquid storage vessel (not shown). The valve 16 is actuated by a pneumatic circuit controlled by a suitable device 18 and normally arranged for automatic operation by the scale 12, in a manner already known in the art.

The lance valve 16 has a stationary outer cylinder or housing 20 whose lower end is positioned higher than the top 15 of the containers 10 to be filled, an inner cylinder or lance 21, which is reciprocatable in the outer cylinder 29 between a position almost entirely within it (Fig. 2) to a position where it is projected almost completely out from it (Fig. l), and a closure valve 22, which is mounted on a rod 23 extending axially through the inner cylinder 21. When the container 19 is placed on the platform 11, the lance 21 is inserted through the bunghole 14 and lowered until the valve 22 is near the bottom of the container 10. The valve 22 is opened, and liquid 13 flows into the container 10 until the predetermined weight is reached; then the automatic device 13 closes the valve 22 and withdraws the lance 21 from the container 10, while wiping the liquid 13 from the lances outer surface.

The stationary housing or outer cylinder 20 The stationary outer cylinder or housing 20 has a long vertical cylindrical passage 25 whose upper end 26 is closed by a cylinder head 27, preferably being sealed by an O-ring 28 that is seated in an annular groove in the cylinder head 27. The lower face of the cylinder head 27 is provided with a central recess 29, to be explained later, and an air inlet opening 30 leads through the housing 20 and head 27, passing in through its side wall and out through its lower face.

A liquid inlet tube 31 enters the housing 20 laterally, adjacent and above the housings lower end 32. Liquid 13 from a large storage container (not shown) thereby flows into a compartment 33 of the passage 25, via the hose 17 and tube 31. A pair of annular members or heads 34 and 35, seal elf the compartment 33 and prevent the liquid 13 from leaking out through the lower end 32 or seeping up into the upper portion of the passage 25.

The upper head 34 is bolted to the housing 20 above the intersection of the side tube 31 with the cylinder 25, and is provided with a spaced-apart pair of outer O-rings 36 and 37, seated in annular grooves and sealing tightly against the Wall of the passage 25. A pair of inner O-rings 38 and 39 are provided on the inner periphery of the upper head 34, the O-ring 38 being a sealing ring and the lower ring 39 a wiping ring, serving to prevent the outer surface of the lance 21 from carrying liquid 13 from the compartment 33 up above the head 34.

A second air inlet 40 is provided adjacent the upper end 41 of the head 34. Thus the cylinder heads 27 and 34- and the passage 25 provide an air cylinder 42 having an upper air inlet 30 and a lower air inlet 40.

The lower head 35 is bolted in place between the liquid inlet tube 31 and the lower end 32 of the housing 20. Preferably, the lower head 35 is provided with an outer O-ring 43, forming a tight seal against the housing wall, and a pair of inner O-rings 44 and 45, the upper O-ring 44 being a sealing ring and the lower ring 45 a wiping ring to wipe the outside of the lance 21. The liquid 13 carried up from the container 10 then falls back into the container 10, where it had been weighed as part of the net contents and where it therefore belongs. There are no ledges or obstructions to prevent the liquid 13 from falling off the end of the lance 21, and the O-ring 44 assures clean wiping and accurate weight of the containers net contents.

The lance or inner cylinder 21 The lance or inner cylinder 21 is preferably made up of two tubes 50 and 51 welded to each other at 52. The lower lance tube 50 is slidably mounted for reciprocating movement through the upper and lower heads 34 and 35, sealing and wiping being provided by the O-rings 38, 39, 44, and 45. The upper tube 51 is of smaller outside diameter than the lower tube 50 and has radial openings or inlet ports 53, through which the liquid 13 may enter the interior of the lance 21 from the compartment 33 when the openings 53 are below the upper head 34 and are uncovered (see Figs. 4 and An annular fitting 54 may be threaded into the upper end of the upper tube 51. The fitting 54 preferably has a radial end flange 55 providing a fiat upper face 56 and a lower shoulder 57.

The inner periphery of the fitting 54 is provided with an O-ring 58, making an airtight seal with the rod 23, which is reciprocatable therethrough.

A lance closure sleeve 60 is slidably mounted around the upper tube 51, its upward movement being limited by the annular shoulder 57 and its downward movement being limited by a shoulder 61, which may be provided by the upper end of the lower tube 50. When the sleeve 60 abuts the shoulder 61, as it normally does, it closes the inlet ports 53. When it abuts the shoulder 57, the ports 53 are opened. An O-ring 62 is seated in an annular groove in the sleeve 60 to seal against the upper tube 51, while an O-ring 63 in the outer periphery of the tube 51 assures a tight seal when the sleeve 60 is closing the ports 53. The sleeve 60 also has a radial flange 65 at its upper end, providing an upper shoulder 66 and a lower shoulder 67.

The closure valve 22 and rod 23 The closure valve 22 is secured to the lower end of the long rod 23, which extends axially through the entire lance cylinder 21. The valve 22 has a conical taper 70 terminating in a rounded lower end '71, this shape aiding; in properly positioning the bunghole 14 relative to the lance 21. If the lance 21 and the bunghole 14 are slightly out of position, the tapered valve end 79 will enter the bunghole 14 anyway and will force the container 10 to move the amount necessary to assure exact alignment. Thus, the valve is self-positioning to some extent.

The valve 22 is provided with a shoulder 72 (see Fig. 5) adapted to engage the lower end 73 of the lance 21. The outer diameter of the shoulder 72 and of the adjacent portion 74 is the same as that of the lance tube 54), while the width of the shoulder 72 is the same as the thickness of the tube 50, so that the outer diameter of the valves set-back portion 75 is approximately equal to the inner diameter of the tube 50. An O-ring 76 in the set-back portion 75 insures a tight seal between the valve 22 and tube 50 in the valves closed position. it is obvious that once the valve 22 is closed with its shoulder 72 against the lower end 73 of the tube 50, any upward movement of the rod 23 and valve 22 will carry the lance 21 up with them.

The upper end of the rod 23 is secured to a piston 89 having an Oring 81 mounted in its outer periphery so as to engage the cylinder 42 and divide it at all times into two chambers 82 and 83 which vary in size according to the position of the piston 80. The piston 30 is operated pneumatically, in a manner soon to be described, for projecting and retracting the lance 21 and for opening and closing the valve 22. The upper end of the piston is provided with a reduced end 84 adapted for reception into the pocket 29 in the cylinder head 27, an O-ring 85 cushioning any shock. The length of this end portion 84 is greater than the depth of the pocket 29, so that the upper piston shoulder 86 will not strike the outer annular portion 87 of the cylinder head 27.

The upper ends of a pair of springs and 91 are seated against the lower piston shoulder 88 and around the collar portion 89. The lower end of the outer coil spring 90 terminates against the shoulder 66 of the sleeve flange 65, While the lower end of the inner coil spring 91 terminates against the upper shoulder 56 of the fitting 54. Both springs 90 and 91 are always under compression and therefore tend to hold the valve 22 closed and the sleeve 69 against the shoulder 64, so that the ports 53 are closed, other factors being equal. If there is any air failure, the valve 22 and sleeve 60 will move to or remain in their closed positions.

Operation Starting with the lance 21 in its fully raised position, as shown in Fig. 3, the spring 91 holds the closure valve 22 tight against the lower end 73 of the tube 50, and the spring 90 holds the sleeve 60 closed around the ports 53.

d The ()-rings 75, 62, and 63 provide a tight seal at each of these closures.

When a container is placed on the scale platform 11 and its bunghole 14 located beneath the lance 21, air under pressure is sent through the upper air inlet 30 into the upper air chamber 82, and the lower air chamber 83 is bled to atmospheric pressure. The downward pressure against the piston 80 causes it to move downwardly, carrying with it the rod 23 and the lance 21. The spring 91 keeps the valve 22 closed, while the spring 90 keeps the ports 53 closed until the position shown in Fig. 4 has been reached.

Before the Fig. 4 position is reached, the lance 21 moves down until its lower end 73 projects well beyond the lower end 32 of the housing 20, the valve 22 still being closed. After a while, the lower shoulder 67 of the sleeve flange 65 abuts the upper shoulder 41 of the upper head 34 and ends the free movement of the piston 84). From then on, the air pressure must work against spring pressure. The spring 90, being more extended, is the first to be compressed; so further movement of the piston 80 downwardly continues to send the lance 21 still further down and, since the sleeve 60 cannot move further down, the ports 53 are uncovered, this phase terminating in the position shown in Fig. 4. The ports d3 are now open, and the liquid 13 can now enter the lance 21. After the first dispensing operation, liquid will be present inside the lance 21 at all times, and this uncovering will then serve to prepare the apparatus for subsequent How.

The air pressure in the chamber 82 continues to move the piston 3% down, and the inner spring 91 is then compressed. Since the upper shoulder 66 of the flange 65 engages the lower shoulder 57 of the flange 55, the lance tube 21 can move no further; so the valve 22 is Pushed away from the end 73 of the fully extended lance 21, until the springs 90 and 91 are compressed as far as air pressure and their own size permits. (Fig. 5. Note that the valve 22 cannot open until the lance 21 has been fully extended.) Liquid 13 now flows freely into the container 10 until the desired quantity is inside, as indicated by the scale 12.

When the filling has been completed, it is desired to close the valve 22 and Withdraw the lance 21. Therefore, the air pressure to the inlet 30 at the upper end of the cylinder 42 is turned oif, and the air is preferably allowed to bleed away evenly to atmospheric pressure. At the same time, air under pressure is supplied to the chamber 83 through the lower inlet 40. These operations may be done automatically by well-known control devices 18. The force of the air entering through the inlet 40, combined with the force of the inner spring 91, will immediately close the valve 22. (Fig. 5. In fact, the spring 91 is so balanced that the valve 22 will be closed if air fails completely, so that the liquid 13 will not continue to run out.) The air pressure then moves the piston 89 farther up, relieving the tension on the outer spring 90, so that the sleeve 60 will close the ports 53. Further movement of the piston 80 will cause the valve 22, lance 21, sleeve 60, rod 23, and piston 80 to move together upwardly as a unit to their fully retracted position. (Fig.3.)

As the lance 21 is retracted, the wiping O-rings 39 and 45 wipe oi? the outside of the lance tube 50. The O-ring 45 first wipes off the liquid 13 carried up from the container and restores it to the container 10. The O-ring 39 wipes off the tube 50 as it passes the filling compartment 33 of the housing 20.

From the above description it is obvious how the present invention prevents turbulence and aeration, how it conserves space by telescoping, how it prevents leakage and wipes itself clean, so as to give accurate measurement, how it is, to some extent, self-locating, and how it operates as a self-contained unit without any eccentric loads. Since it is pneumatic and since all parts can be made from stainless steel, brass, and other non-sparking metals, it is safe for use with inflammable and explosive liquids.

It is fail-safe, since if the air fails, it shuts itself down and the springs and 91 close both the foot valve 22 and the sleeve valve 60.

If the lance 21 misses the bunghole 14, the air pressure builds up until the thrust of the lance 21 against the container 14 and through the container to the platform 11 equals the cut-off weight for which the scale is set. Then the automatic device retracts the lance 21 automatically. It will not open, of course, because it does not get extended that far.

To those skilled in the art to which this invention relates, many changes in construction and widely differing embodiments and applications of the invention Wlll suggest themselves without departing from the spirit ano scope of the invention. The disclosures and the description herein are purely illustrative and are not intended to be in any sense limiting.

What is claimed is:

l. A filling valve for liquids, including in combination: a stationary housing having a vertical passage, with a closed upper end, said passage being divided into an upper air cylinder and a lower liquid compartment having a liquid inlet, said air cylinder having a pair of inlet-outlet means; a lance tube slidably mounted in said passage, said tube having liquid inlet means through an upper portion of its walls; a sleeve slidably mounted around said upper portion of said lance tube for opening and closing said inlet means; a closure valve adapted to open and close off the lower end of said lance tube; piston means rigidly secured to said closure valve and movable in said air cylinder and dividing said cylinder into first and second air chambers; and means normally urging the upper end of said sleeve away from said piston means and normally urging said lance tube away from said piston means.

2. A filling valve for liquids, including in combination: a stationary housing having a vertical passage, with a closed upper end, said passage being divided by a sealing member into an upper air cylinder and a lower liquid compartment having a sealing member at its lower end and a liquid inlet through its side wall, said air cylinder having a pair of inlet-outlet means, one adjacent the upper end thereof and the other adjacent the lower end thereof; an open-ended lance tube slidably mounted in and in liquid sealing relation with said sealing members, said tube having liquid inlet means through an upper portion of its walls and stop means above and below said inlet means; a tubular sleeve slidably mounted around said upper portion of said lance tube for movement between said stop means, for opening and closing said inlet means; a closure valve adapted for movement to open and close off the lower end of said lance tube; piston means secured rigidly to said closure valve and movable in said air cylinder, dividing said cylinder into first and second air chambers; yieldable means urging away from said piston means the upper end of said sleeve and urging away said lance tube from said piston means; and means to introduce air under pressure alternately to said air inlet-outlet means while bleeding off air through the other said air inlet-outlet means, for reciprocating said lance relative to said housing, said sleeve relative to said lance, and said valve relative to said lance.

3. A filling valve for liquids, including in combination: a stationary housing having a vertical passage, with a closed upper end, said passage being divided by a sealing member into an upper air cylinder and a lower liquid compartment having a sealing member at its lower end and a liquid inlet through its side wall, said air cylinder having a pair of inlet-outlet means, one adjacent the upper end thereof and the other adjacent the lower end thereof; an open-ended lance tube slidably mounted in and in liquid sealing relation with said sealing members, said tube having liquid inlet means through an upper portion of its walls and stop means above and below said inlet means; a tubular sleeve slidably mounted around said upper portion of said lance tube for movement between said stop means, for opening and closing said inlet means; a closure valve adapted for movement to open and close oil the lower end of said lance tube; rod means secured to said closure valve and extending axially through said lance tube and out the upper end thereof; piston means secured to the upper end of said rod and movable in said air cylinder and dividing said cylinder into first and second air chambers; a pair of spring means seated against the lower face of said piston means, one urging away therefrom the upper end of said sleeve and the other urging away said lance tube; and means to introduce air under pressure alternately to said air inlet-outlet means while bleeding off air through the other said air inlet-outlet means, for reciprocating said lance relative to said housing, said sleeve relative to said lance and said rod means and valve relative to said lance.

4. The valve of; claim 3 in which said'passage is cylindrical and said sealing members are annular and have a coaxial passage therethrough, with at least one O-ring sealing the outer periphery of each said sealing member to said housing passage, each said sealing member having a pair of O-rings mounted on their inner periphery, for sealing with said lance tube and for wiping said tube clean as it moves upwardly.

5. The valve of claim 3 in which said lance tube has a lower main portion of larger diameter and an upper portion of smaller diameter meeting in a perpendicular annular shoulder, said liquid inlet means being in said upper smaller-diameter portion; said sleeve being limited in its downward movement by said shoulder.

6. The valve of claim 5 in which said lance tube is provided with an annular O-ring between said inlet means and said shoulder, for sealing with said sleeve when the latter is in its closed position and in which said sleeve has an O-ring in its inner wall always in contact with said upper lance tube portion and always above said liquid inlet means.

7. The valve of claim 5 in which said lance tube has an enlarged upper annular end whose lower surface acts as the upper step for said sleeve and whose upper surface bears against one said spring.

8, The valve of claim 6 in which said sleeve has an enlarged upper end of wider diameter than said lance tubes enlarged upper end, the upper surface of said sleeve end bearing against the other said spring, the two springs being coaxial, the lower surface of said sleeve end being adapted to engage the upper of said sealing members for stopping movement of said sleeve, while said lance tube can move further down and open said inlet means.

9. The valve of claim 3 wherein said closure valve has a shoulder adapted to fit against the lower end of said lance tube, so that upward movement of said closure valve produces upward movement of said lance tube.

10. The valve of claim 9 wherein said closure valve has an outer diameter equal to that of the lower part of the lance tube, said shoulder having substantially the thickness of said lance tube walls, with a reduced portion thereabove having an annular O-ring seal mounted therein.

11. The valve of claim 9 in which the lower end of said closure valve is tapered eonically toward a lower rounded end.

12. A filling valve for liquids, including in combination a stationary housing having a first vertical cylindrical passage, with a closed upper end having a first air inlet opening therethrough, an open lower end having a first annular head therein with a second vertical cylindrical passage therethrough, co-axial with said first passage, a radial inlet passage for liquids leading into said first cylindrical passage adjacent and above said first head, a second annular head in said first passage above said liquid inlet passage having a third vertical cylindrical passage coaxial with said first passage and the same diameter as said second passage, and a second air inlet passage through said housing leading into said first passage adjacent and above said second head; a lance tube slidably mounted in said second and third vertical passages and having a fourth vertical passage therethrough, said tube having an upper portion of smaller outer diameter than the main portion thereof with perforations thercthrough for the passage of liquid from said first passage into said fourth passage, a first shoulder where the main portion ends and at its upper end an enlarged annular end providing a second shoulder on its lower face; a tubular sleeve slidably mounted around said upper portion of said lance tube for movement between said first and second shoulders, said sleeve in its lower position being adapted to close off said perforations and in its upper position to open said perforations, and having an enlarged upper end extending radially beyond the enlarged annular end of said lance; a closure valve adapted to close off the lower end of said lance tube, the upper part of said valve being adapted to fit up into said lance tube and seal against leakage therebetween, said upper part having a radially extending annular shoulder forming the top of a lower portion and having substantially the same outer diameter as said lance tube, the lower portion terminating in a generally conical end with a rounded apex; a rod rigidly secured to the upper end of said closure valve and extend ing co-axially through said lance tube and spaced from its inner walls, said rod being longer than said lance tube; a piston secured to the upper end of said rod and movable in said first passage and dividing said first passage at all times into first and second chambers; a pair of eo-axial coil springs of different diameter with one end seated against the lower face of said piston and the opposite ends seated with the larger-diameter spring bearing against the enlarged upper end of said sleeve and the smaller-diameter spring bearing against the enlarged upper end of said lance tube; and means to introduce air under pressure alternately to one of said air inlet passages while bleeding off air through the other passage, so as to move said lance down through the lower end of said housing, expose its perforations, by compressing said larger-diameter spring, for sending liquid into it from said first passage adjacent said liquid inlet, and then pushing said closure valve further down to open it, by compressing said smaller-diameter spring, and subsequently by alternating the introduction and bleeding of air to close said closure valve, retract it so as to raise said lance and close off said perforations by said sleeve and wipe liquid from around the outer diameter of said lance so that the liquid below said first head falls below said valve and that from the upper portion of said lance falls into said first passage between said heads.

13. A filling valve for liquids, including in combination: a stationary housing having a first vertical cylindrical passage, with a closed upper end having a first air inlet opening therethrough, an open lower end having a first annular head therein with a second vertical cylindrical passage therethrough, co-axial with said first passage, having a pair of O-rings mounted therein and having on its outer periphery an O-ring seal to the inner wall of said housing, a radial inlet passage for liquids leading into said first cylindrical passage adjacent and above said first head, a second annular head in said first passage above said liquid inlet passage having a pair of O-rings mounted in its outer wall in engagement with said inner cylindrical passage and a third vertical cylindrical passage co-aXial with said first passage, the same diameter as said second passage, and having a pair of O-rings mounted therein, and a second air inlet passage through said housing leading into said first passage adjacent and above said second head; a lance tube slidably mounted in said second and third vertical passages and having a fourth vertical passage therethrough, said tube having an upper portion of smaller outer diameter than the main portion thereof with perforations therethrough for the passage of liquid from said first passage into said fourth passage, a first shoulder where the main portion ends and an O-ring in the wall of said upper portion between said shoulder and said perforations, and having at its upper end an enlarged annular end providing a second shoulder on its lower face, the inner wall of said end having an O-ring mounted therein; a tubular sleeve slidably mounted around said upper portion of said lance tube for movement between said first and second shoulders, said sleeve in its lower position being adapted to close off said perforations and in its upper position to open said perforations, and having an enlarged upper end extending radially beyond the enlarged annular end of said lance and having an O-ring mounted in its inner wall; a closure valve adapted to close off the lower end of said lance tube, said valve having a solid body, the upper part of which is adapted to fit up into said lance tube and having an O-ring adapted to seal against leakage therebetween, said upper part having a radially extending annular shoulder forming the top of a lower portion and having substantially the same outer diameter as said lance tube, the lower portion terminating in a generally conical end with a rounded apex; a rod rigidly secured to the upper end of said closure valve and extending co-axially through said lance tube and spaced from its inner walls, said rod being longer than said lance tube; a piston secured to the upper end of said rod and movable in said first passage and dividing said first passage at all times into first and second chambers, said piston having an O-ring in its outer periphery and having a reduced upper end portion adapted to seat in the upper closed end of said housing, said upper end portion of said piston being longer than said recess and having an O-ring in its outer wall adapted to act as a cushion in the walls of said recess; a pair of co-axial coil springs of different diameter with one end seated against the lower face of said piston and the opposite ends seated with the larger-diameter spring bearing against the enlarged upper end of said sleeve and the smaller-diameter spring bearing against the enlarged upper end of said lance tube; and means to introduce air under pressure alternately to one of said air inlet passages while bleeding oif air through the other passage, so as to move said lance down through the lower end of said housing, expose its perforations, by compressing said larger-diameter spring, for sending liquid into it from said first passage adjacent said liquid inlet, and then pushing said closure valve further down to open it, by compressing said smaller-diameter spring, and subsequently by alternating the introduction and bleeding of air to close said closure valve, retract it so as to raise said lance and close oif said perforations by said sleeve and wipe liquid from around the outer diameter of said lance so that the liquid below said first head falls below said valve and that from the upper portion of said lance falls into said first passage between said heads.

No references cited. 

